1. Field
Embodiments of the present invention relate to a secondary battery, and more particularly, to a secondary battery capable of preventing the movement of an electrode assembly and the bending of an electrode tab in the interior of a case.
2. Description of the Related Technology
Recently, a variety of batteries has been used as power sources for small-sized electronic devices. Particularly, batteries such as lithium secondary batteries, which are small in size and large in capacity, are frequently used as power sources for mobile phones, notebook computers, camcorders and the like.
A lithium secondary battery is typically formed by accommodating an electrode assembly in the interior of a case. such as a pouch or a can, and injecting an electrolyte into the case. The electrode assembly may be divided into a wound-type electrode assembly and a stacked-type electrode assembly. The wound-type electrode assembly is typically formed by interposing a separator between positive and negative electrode plates and winding them in a jelly-roll shape. On the other hand, the stacked-type electrode assembly is typically formed by stacking a plurality of structures, each having positive and negative electrode plates, and a separator interposed therebetween.
In the wound-type electrode assembly, a finishing tape is typically attached on outer end surfaces of the electrode assembly so as to fix a portion to be finished. The electrode assembly having the finishing tape attached thereto is accommodated in a case, and an electrolyte is injected into the interior of the case. Then, the case is tightly sealed.
However, in the secondary battery described above, the electrode assembly is not adhered closely to the inner surface of the case. Hence, if an impact is applied to the secondary battery from the exterior of the case, the electrode assembly is moved in the interior of the case. Therefore, an electrode tab of the electrode assembly may become bent. Also, because the electrolyte typically serves as a lubricant, the electrode assembly may move inside the case. This occurrence may cause internal short circuits.
Particularly, in a pouch type case, the strength of the case is typically weak, and the safety of the case may be compromised. In case of a medium- or large-sized battery, a large amount of electrolyte can be distributed to a lower portion in a case, and thus unequally distributed in the case. Moreover, in a secondary battery using a pouch-type case, the appearance of the secondary battery may be unequal.